1
The Effect of X–Ray Vertical Angulation on Radiographic Assessment
of Alveolar Bone Loss
M. Mehdizadeh MD*, M. Amintavakoli MD**, M. Allahverdi MD***
ABSTRACT
Introduction: Radiographs provide unique information about the status of periodontium and
permanent records of condition of bone throughout the course of the disease. Interproximal images
record the distance between the Cementoenamel Junction and the crest of the interradicular alveolar
bone, more accurately. The aim of this study was to investigate the effect of different vertical angles
of x-ray tube (0, -10, +10) degrees in horizontal and vertical bite wing techniques in assessment of
bone loss.
Methods: One hundred and twenty bitewing radiographs from 150 interproximal surfaces from 10
dried skull were by three degrees (0, -10, +10) prepared. The level of alveolar bone loss was
measured using ruler on the skulls and radiographs and data were registered. Type of bone loss was
horizontal.
Results: The maximum differences between invitro and radiographic findings were +3 and -2.745
mm. In all areas, radiographic data were less than clinical diameters. In all areas, by using zero
degree vertical angulation, there was less difference between mean of radiographics and clinical
measurements.
Conclusions: with changing vertical angulations, using 0, +10, and -10 degrees, a wide range of
measures (2.75-3mm) in amount of alveolar bone loss were ohtained for evaluating periodontal
disease or following them up, accurate and reproducible images are necessary. In this study we
concluded that zero vertical angulation degree decrease the angulation errors and reduce
understimation of radiographic assessment of alveolar bone loss.
[Dental Research Journal (Vol. 2, No. 2, Winter 2006)]
Introduction
Along with marginal inflammation,
periodontal
pocket
formation,
and
attachment loss, are primary features of
periodontitis. The height of alveolar bone
may be evaluated by intrasurgical
inspection or by radiographic examination.
How ever radiographic assessment tends to
underestimate the amount of bone loss 1, 2.
Projection geometry of serial radiographs
should be standardized to minimize
measurement errors 3, 4. Such errors are
often
difficult to be distinguished from biologic
changes 5.
Advanced radiographic analysis by
measurement of linear distance or digital
subtraction require highly standardized
projection. Whereas digital subtraction
analysis can be used only to assess
differences between at least two
radiographs, linear measurements can be
used to assess bone status on single
radiographs 6, 7. How ever, even in single
radiographs, projection geometry may
influence validity of interpretation 8, 9.
*Assistant Professor, Department 0f Oral and Maxillofacial Radiology, Isfahan Dentistry Faculty, University of Medical Sciences,
Isfahan, Iran.
**Associated Professor, Department 0f Oral and Maxillofacial Radiology, Shahid Beheshti Dentistry Faculsty, University of
Medical Sciences, Tehran, Iran.
*** Dentist
2
The clinical evaluation and assessment of a
patients periodontal status requires that
information be collected from several
diagnostic tests and then assimilated into a
diagnostic impression. One commonly used
diagnostic procedure is the radiographic
examination, which not only offers
information about the patients present
condition but also affords a practitioner the
ability for longitudinal assessment of
changes or stability within the supporting
periodontium.
This matter of fact that radiographs may be
useful to detect minute changes within the
alveolar bone, has led to studies on
radiographic techniques such as subtraction
radiography and radiometric analysis,
however, most practitioners still depend
heavily on routine intraoral radiographic
techniques for periodontal assessment 10.
To optimize diagnostic information from
routine
radiographic
examination,
appropriate radiograph of the highest
quality should be used. Radiographs play an
integral role in assessment periodontal
disease. They provide unique information
about the status of periodontium and
permanent records of condition of bone
throughout the course of the disease.
Interproximal cemento enamel images
record the distance between the junction
(CEF) and the crest of the interradicular
alveolar bone, more accurately.
The aim of this study was to assess the
validity of linear measurement of alveolar
bone loss on horizontal and vertical
bitewing radiographs by using three vertical
angles (0, –10, and +10) by real
measurement on skull
Materials and Methods
At first, 10 dried skull were prepared from
Anatomy
Department
of
Medicine
University of Isfahan, Iran. The acceptance
conditions of skulls were existing teeth and
alveolar bone resorption.
The resorption of alveolar crests were
measured mesially and distally by exact
ruler by 1% accuracy. For each area, every
place was measured three times and their
means were registered.
We concluded the distance between CEJ
and alveolar crest type of bone loss was
horizontal and we concluded the mean bone
loss of buccal and lingual plate.
Skulls were stabilized so that their sagital
plans were at right angle to horizontal plans
and occlusal plans were parallel to
horizontal plans. For preparing horizontal
and vertical bitewing, we used AGFA,
periapical, E speed, size 2 films.
120 vertical and horizontal Bite wings
radiography were prepared by three vertical
angles (0, +10, -10 degrees). Skulls were
stabilized so that their conditions did not
move after each radiography. For each
radiograph, mA and kvp were the same. For
preparing soft tissue equivalent, we used
6mm of vax. We used trophy x- ray unit
and films were processed by peri – pero
automatic processor.
150 areas with periodontal lesions, were
survived in posterior teeth.
Radiographs were viewed by view box.
The distance between CEJ and alveolar
crest were measured mesially and distally
using an exact ruler and data were
registered. Statistical analysis was done
using t-student test.
Results
In this study, we compaired amounts of
alveolar bone loss in vitro and in bite wing
radiography, using three angles (0 , -10 ,
+10) in 150 teeth surfaces. Data are shown
in tables 1 and 2:
3
The Effect of X–Ray Vertical…
Table 1: Different means among 3 groups by three angles (0, -10 , +10) , in teeth of maxilla.
Group
Mean
+10 angle
0.3521
-10 angle
0.5625
0 anlge
0.125
SD: standard deviation.
SD
0.9442
0.8780
0.4684
T
-1.116
6.017
1.109
DF
47
47
47
P
0.270
0.000
0.273
Table 2: Different means among 3 groups by three angles (0, -10, +10) in teeth of mandible.
Group
Mean
+10 angle
0.5376
-10 angle
0.1376
0 anlge
0.09
SD: standard deviation.
SD
0.8572
1.0027
0.7049
Conclusion
one of the methods of periodontal disease
diagnosis is radiography, by which the level
of alveolar bone resorption can be measured
in per apical radiography. Multi factors are
effective on determining the amount of
alveolar bone loss such as the angle of
central x- ray, type of film, processing, and
the skills of clinician.
One of the most useful techniques in
evaluation of periodontal disease is bite
wing technique 10. The vertical angle of
bitewing radiography effects on estimating
of alveolar bone loss.
In this study we used three vertical angles
(0, -10, +10).
In maxilla, by using zero vertical angle,
there was a little difference between real
alveolar bone loss and radiographic
measurement
(p-value=0.237).
In
Mandible, by using zero vertical angle,
there was no difference between real
alveolar bone loss and radiographic
measurements.
SM Jenkins concluded that 0 to 20 degrees
vertical angulations caused decrease in
distance between crest and CEJ 11. Schei
concluded that changinges 10 degrees in
vertical angulations in anterior teeth, had
less effect on measurement of alveolar bone
loss than posterior teeth 12.
Khalid Almas concluded in their research
that changing vertical angulations from –10
to +10 will change the amount of alveolar
bone loss from 1. 84 to 3.70 millimeters 13.
T
5.873
1.226
1.169
DF
84
84
84
P
0.000
0.209
0.246
Amin Tavakoli and Mehdizaden concluded
in their study about the effectiveness of
parallel and bitewing Radiographies, using
XCp in measuring alveolar bone loss, that
vertical bitewing was more accurate 14.
Alveolar bone loss, attributable to
periodontitis, can be assessed using intra
oral
radiographs,
however
these
radiographs provide only two dimensional
structures. Changes in the projection
geometry between consecutively obtained
radiographs may lead to different two –
dimensional images of the same three –
dimensional situation.
Such artifacts often are difficult to be
distinguished from pathologic changes.
Hence, the projection geometry of serial
radiographs has to be highly standardized.
Projection artifacts may be caused by
different angulations between the central
beam and film while the relationship
between teeth and film is fixed 15.
In this research, we conclude that by using
zero degree vertical angulation, we had less
difference between radiographic and real
measurements of alveolar bone loss. Also
by using +10 vertical angulation for
Maxilla and –10 degree for Mandible we
had less different by real measurements by
changing vertical angulations. We have
changes in measuring alveolar bone loss
and this phenomena cause false conclusion.
Radiography is not effective lonely and we
need use use other methods such as probing
and…
4
By using film holders, we decrease the
alignment errors, and vertical bitewing by
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The Effect of X–Ray Vertical…
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The Effect of X–Ray Vertical…